This invention relates to a new and improved container end member and to new and improved methods of manufacture of a container end member. More particularly, the invention relates to a one piece container and end member of one piece of metallic sheet material adapted to be associated with a container body member to close one end thereof to provide a container member for goods and having an integral tab portion in the container end member axially displaceable to provide access to the contents of the can.
While container end members of the general type described hereabove have been known for some time, the prior designs have not been entirely satisfactory for many reasons. The primary objective of such designs has been to eliminate the use of a container opening arrangement resulting in a separate part which has in the past often been carelessly disposed of by the person opening the container. It has been recognized heretofore that an integral tab portion in the container end member could be provided by a discontinuous score groove leaving an integral hinge area to enable the tab portion to be pushed inwardly into the interior of the container member by severing along the discontinuous score line with the tab portion remaining integrally connected to the container end member at the hinge area as illustrated by U.S. Pat. No. 2,176,898. Prior constructions of this general type have also included a pair of relatively small diameter circular tab portions located in relatively wide radially inwardly spaced relationship to the exterior rim portion of the container end member and in diametrically opposed spaced relationship. The reason for providing a pair of such circular tab portions is that one of the openings provided thereby serves as a spout to pour out the contents of the container while the other opening serves as a vent to enable air to enter the container. Such circular tab portions have been connected to the container end member by relatively narrow width hinge areas with the result that the hinge areas may be severed when the tab portions are inwardly displaced and the completely separated tab portions fall into the container. Such relatively small diameter tab portions have not provided completely satisfactory pouring spout openings. It has been previously suggested that both tab portions be of the same relatively large diameter so that a completely severed tab portion cannot be removed from the container. The concept of providing two relatively large diameter circular openings has not been acceptable because of problems relating to maintaining the required strength in the container end wall member to prevent buckling to enable satisfactory storage of liquids under pressure without destroying the sealed integrity of the container.
The present invention provides a new and improved container end member which has solved many of the problems of prior art devices by enabling the usage of only one relatively large tab portion connected to the container end member by a relatively large hinge area with the results of: alleviating the possibility of completely severing the tab portion; facilitating ease of opening of the container during severing the tab portion from the container end member with application of relatively small force; locating a portion of the opening relatively closely adjacent the exterior rim of the container end member to facilitate pouring out of the contents especially during drinking of beverages from the container; locating a portion of the opening relatively closely adjacent the central axis of the container end member to facilitate entry of air for pouring out of the contents; providing a large surface area on the tab portion readily receiving a person's finger or thumb to press the tab portion into the container; doming the central wall portion of the container end member into convex axially outwardly extending relationship to the exterior rim portion to facilitate opening of the tab portion and pouring and venting of the container contents while providing maximum strength characteristics facilitating assembly of the container end member on a container body member and handling and storage of the container without damage to the sealed integrity of the contents of the container; and forming the tab portion in concave axially inwardly extending relationship to the exterior rim portion to facilitate severing of the tab portion while providing maximum strength characteristics enabling satisfactory manufacture and assembly of the container end member, pressurization of the container, and handling and storage of the container without damage to the sealed integrity of the contents of the container.